When fixing a tubular door lock in a door, a long latitudinal groove needs to be cut on the side surface of a door so as to fit the lock in, and a turning hole then is cut in the front surface of the door to fit with the intersecting crossed hole of the lock. The "crossed hole" is a rotatable member having a cross-shaped opening.
Usually, locks nowadays manufactured are divided into two sizes--60 mm and 70 mm--representing different distances between its crossed hole and faceplate. Therefore, in order to satisfy different needs, manufacturing two different sizes of locks, retailers are obliged to devote more space for storing them, and buyers, unless having knowledge of locks, may feel at a loss in selecting them.